Sputnik Gall Wasp
- Diplolepis nervosa

The Sputnik Gall is nearly always caused by the cynipid wasp Diplolepis nervosa. It is usually foundon the undersides of the leaves of the Dog-rose (Rosa canina), but occasionally on the upper surface. The gall is more likely to be seen than the adult wasp.

Habitat

Anywhere that the host Dog-rose plant is found.

When to see it

The adult insects emerge from their galls in spring.

Life History

Each gall is, in effect, a hollow, fleshy nursery chamber for a small white grub, the larva of the Diplolepis nervosa gall wasp, which feeds on the chamber wall. The galls appear to detach from the leaves before leaf fall and will lie in the leaf litter until the grub pupates and emerges as the small adult wasp, only about 4 mm long.